by Paulson Games
In the 5th Edition (5E) Blood Angels codex, Furioso Dreadnoughts and Death Company Dreadnoughts can take Blood Talons: The Dreadnought equivalent to lightning claws.
Since Games Workshop didn't release Blood Talon bits officially, players that want to utilize them will have to seek alternate sources or create their own.
As of this writing I am aware of two distinct choices available:
The MKIV Close Combat Arm (left and right)
Unfortunately Forge World charges approximately 10.50 for each arm- and that is before shipping! The other alternative is purchasing a resin kit that includes a set of "Dread Combat Talons" from Paulson Games for approximately 12.00 dollars before shipping. Designed to fit onto an existing Dreadnought arm, these talons will save you quite a bit of money if you all ready have Dreadnought arms available to you! The company also offers mechanized wings and are soon to release Dreadnought Psychic weapon attachments AND riding wolves.
If you haven't all ready, check out Paulson Games!